The present invention relates to a puzzle cut seamed belt useful in electrostatographic reproducing apparatus, including digital, image on image and contact electrostatic printing apparatuses. The present belts can be used as fuser belts, pressure belts, intermediate transfer belts, transfuse belts, transport belts, developer belts, photoreceptor belts, and the like. Preferably, the puzzle cut seam is secured via an ultraviolet curable adhesive. Also, preferably, the adhesive is cured via ultraviolet light. In a particularly preferred embodiment, the puzzle cut seam has a pull strength of from about 15 to about 50 pounds/inch.
In a typical electrostatographic reproducing apparatus such as electrophotographic imaging system using a photoreceptor, a light image of an original to be copied is recorded in the form of an electrostatic latent image upon a photosensitive member and the latent image is subsequently rendered visible by the application of electroscopic thermoplastic resin particles which are commonly referred to as toner. Generally, the electrostatic latent image is developed by bringing a developer mixture into contact therewith. Toner particles are attracted from the carrier granules to the latent image forming a toner powder image thereon. Alternatively, a liquid developer material may be employed. After the toner particles have been deposited on the photoconductive surface, in image configuration, the developed image is transferred to a receiving copy substrate. The image is subsequently fused to a copy substrate by the application of heat in combination with pressure.
Belts, sheets, films and the like are important to the xerographic process. In addition, belt function is very much affected by the seam of the belt. For example, belts formed according to known butting or overlapping techniques provide a bump or other discontinuity in the belt surface leading to a height differential between adjacent portions of the belt, of 0.010 inches or more depending on the belt thickness. This increased height differential leads to performance failure in many applications. A bump, surface irregularity, or other discontinuity in the seam of the belt may disturb the tuck of the cleaning blade as it makes intimate contact with the photoconductive member surface to effect residual toner and debris removal. This may allow toner to pass under the blade and not be cleaned. Furthermore, seams having differential heights may when subjected to repeated striking by cleaning blades, cause photoconductive member cycling speed disturbance which affects the crucial photoconductive belt motion quality. Moreover, seams with a bump or any morphological defects can facilitate the untransferred, residual toner to be trapped in the sites of seam surface irregularities. The seam of a photoreceptor belt which is repeatedly subjected to the striking action by a cleaning blade under machine functioning conditions has triggered the development of pre-mature seam delamination failure. As a result, both the cleaning life of the blade and the overall service life of the photoreceptor belt can be greatly diminished. In addition, the copy quality of image printout can be degraded. Moreover, such irregularities in seam height provide vibrational noise in xerographic development which disturb the toner image on the belt and degrade resolution and transfer of the toner image to the final copy sheet. This is particularly prevalent in those applications requiring the application of multiple color layers of liquid or dry developer on a photoreceptor belt, which are subsequently transferred to a final copy sheet. In addition, the discontinuity in belt thickness due to the presence of an excessive seam height yields variances of mechanical strength in the belt as well as reducing the fatigue flex life of the seam when cycling over the belt module support rollers. Further, the seam discontinuity or bump in such a belt may result in inaccurate image registration during development, inaccurate belt tracking and overall deterioration of motion quality, as a result of the translating vibrations.
Moreover, belts have been prepared in the past by ultrasonic welding which requires high temperature curing of the material between the seam. Such high temperatures cause spattering of the melted material which forms peaks in the seam area. These peaks result in disturbance of components such as corotron wires in the case of charging a photoreceptor belt. Such high temperatures also tend to disturb the orientations of the photoreceptor material. For example, many photoreceptors comprise biaxially oriented polyethylene terephthalate (PET). The high temperatures necessary for curing tend to disturb the orientation of the PET causing a ripple in the seam area. Under machine tension, this ripple is distributed along the length of the belt.
The belts herein comprise ultraviolet curable adhesives. Therefore, there is no need for use of such high temperatures used in ultrasonic welding. Accordingly, the belt material is not disturbed and the ripple effect is reduced or eliminated. Further, by use of ultraviolet curable adhesives, spattering of melted material in the seam area is reduced or eliminated, resulting in a decrease in the disturbance of components with which the belt may come in contact. In addition, by use of the ultraviolet curable adhesives, a strong bond is formed, resulting in a significant increase in pull strength and flex life. Further, the height difference between the puzzle cut seam members and adjacent portions of the belt is reduced to nearly nil, resulting in a smooth seam, increase in flex life of the belt, and little or no ripple effect.
However, currently belt seams using ultraviolet curable adhesives require relatively long cure times, for example, up to about 30 minutes. This increases belt fabrication time, resulting in an inefficiency in belt production.
U.S. Pat. No. 5,487,707 relates to an endless flexible seamed belt comprising puzzle cut members, and further comprising a bonding between adjacent surfaces by an ultraviolet cured adhesive.
U.S. Pat. No. 5,514,436 relates to an endless flexible seamed belt having puzzle cut seams and wherein the seam is of a substantially uniform thickness as the rest of the belt.
U.S. Pat. No. 5,549,193 relates to an endless flexible seamed belt formed comprising puzzle cut members, wherein at least one receptacle has a substantial depth in a portion of the belt material at the belt ends.
Although the above references teach interlocking seams which provide for decreased inherent seam height, increased seam strength, decreased surface roughness at the seam, and increased continuity at the seam, there still exists a need for a seam which has increased seam bonding strength to prevent premature delamination, tearing or rupture. Further, there is a need for an improved belt having a seam which provides a decreased or eliminated ripple effect. In addition, it is desired to provide a seam with virtual nil thickness differential with the main body of the belt, as well as a belt with good tensile and bending flexibility. Moreover, there is a need for a belt which is easily and quickly fabricated.